This article is 【Python Language foundation 】 Column articles , Mainly the notes and exercises in class
Python special column Portal
The experimental source code has been in Github Arrangement
utilize abc library , Design abstract class Shape, stay Shape Define abstract methods in getArea() And perimeter getPerimeter(), Then let Triangle、Rectangle、Circle Inherit separately Shape Class and override functions , among Triangle The three sides of class input need to judge whether the sum of the two sides is always greater than the third side . After designing the four classes , Create a new object in the main function and call to calculate the perimeter and area
""" @Author: Zhang Shier @Date:2022 year 05 month 27 Japan @CSDN: Zhang Shier @Blog:zhangshier.vip """
import abc
import math
# abstract class , use abc library , Just declare the function , There is no need to write specific functions , It's not enough . similar C+ Pure virtual function
class Shape ( metaclass=abc.ABCMeta ):
# area
@abc.abstractmethod
def getArea(self):
pass
# Perimeter
@abc.abstractmethod
def getPerimeter(self):
pass
# triangle
class Triangle ( Shape ):
def __init__(self, a, b, c):
self.a = a
self.b = b
self.c = c
def getArea(self):
return 0.25*math.sqrt ( (self.a + self.b + self.c)*(self.a + self.b - self.c)*(self.b + self.c - self.a)*(
self.a + self.c - self.b) )
def getPerimeter(self):
return self.a + self.b + self.c
# Judge the trilateral relationship
def judgeInput(self):
a1 = self.a + self.b - self.c
a2 = (self.a - self.b) - self.c
b1 = self.b + self.c - self.a
b2 = (self.b - self.c) - self.a
c1 = self.a + self.c - self.b
c2 = (self.a - self.c) - self.b
if (a1 > 0 and a2 < 0) and (b1 > 0 and b2 < 0) and (c1 > 0 and c2 < 0):
return True
else:
return False
# rectangular
class Rectangle ( Shape ):
def __init__(self, a, b):
self.a = a
self.b = b
def getArea(self):
return self.a*self.b
def getPerimeter(self):
return (self.a + self.b)*2
# round
class Circle ( Shape ):
def __init__(self, r):
self.r = r
def getArea(self):
return 3.14*self.r ** 2
def getPerimeter(self):
return 2*math.pi*self.r
if __name__ == '__main__':
a1, a2, a3 = map ( int, input ( " Please enter three sides of triangle :" ).split ( " " ) )
t1 = Triangle ( a1, a2, a3 )
if t1.judgeInput ():
print ( f" Triangle area ={
t1.getArea ()}" )
print ( f" The perimeter of the triangle ={
t1.getPerimeter ()}" )
else:
print ( " The input length of three sides cannot form a triangle " )
b1, b2 = map ( int, input ( " Please enter both sides of the rectangle :" ).split ( " " ) )
r1 = Rectangle ( b1, b2 )
print ( f" Rectangular area ={
r1.getArea ()}" )
print ( f" The perimeter of the rectangle ={
r1.getPerimeter ()}" )
r1 = int ( input ( " Please enter the radius of the circle r1:" ) )
c1 = Circle ( r1 )
print ( " Round area %.2f"%c1.getArea () )
print ( " Circumference %.2f"%c1.getPerimeter () )
To design a “ Supermarket inventory management system ”, Requirements are as follows ：
Design three classes respectively , Sold out category , Inventory class , Manage commodity categories . In the managed goods category, you can save the sold and inventory information through two lists . After through Menu Menu call required 7 Features , Which is modified 、 Delete 、 When selling function calls , You need a first call check() Function to determine whether the product exists
""" @Author: Zhang Shier @Date:2022 year 05 month 27 Japan @CSDN: Zhang Shier @Blog:zhangshier.vip """
# Define inventory class
class Goods:
# Parameterized structure initialization
def __init__(self, name, num, cin, cout):
self.name = name
self.num = num
self.cin = cin
self.cout = cout
def __str__(self):
state = " It's sold out "
if self.num == 0:
return ' name ：%s , Number ：%d %s, Purchase price ：%.2f , Selling price ：%.2f '%(self.name, self.num, state, self.cin, self.cout)
else:
return ' name ：%s , Number ：%d , Purchase price ：%.2f , Selling price ：%.2f '%(self.name, self.num, self.cin, self.cout)
# Sold out category
class gGoods:
def __init__(self, name, gnum, gcin, gcout):
self.name = name
self.gnum = gnum
self.gcin = gcin
self.gcout = gcout
def __str__(self):
return ' name ：%s , Quantity sold ：%d , Purchase price ：%.2f , Selling price ：%.2f '%(self.name, self.gnum, self.gcin, self.gcout)
# Define and manage commodity classes
class GoodsManager:
go = [ ] # stock
js = [ ] # Sell out
# Construction method , Initialization plus three items
def init(self):
self.go.append ( Goods ( ' milk ', 5, 40, 60 ) )
self.go.append ( Goods ( ' Box lunch ', 5, 10, 60 ) )
self.js.append ( gGoods ( ' noodles ', 1, 30, 60 ) )
# menu
def Menu(self):
self.init ()
print ( '\" Supermarket inventory management system \" menu ：' )
print ( "1. Show all products " )
print ( "2. Add a new item " )
print ( "3. Modify product information " )
print ( "4. Delete item " )
print ( "5. Selling goods " )
print ( "6. Summary " )
print ( "-1. sign out " )
print ( "***********************************" )
while True:
SN = int ( input ( " Please enter the operation serial number ：" ) )
if SN in [ -1, 1, 2, 3, 4, 5, 6 ]:
if SN == -1:
print ( " Has been withdrawn from " )
break;
if SN == 1:
self.Show_all ()
elif SN == 2:
self.Add ()
elif SN == 3:
self.Modify ()
elif SN == 4:
self.Delete ()
elif SN == 5:
self.Shop ()
elif SN == 6:
self.Summary ()
else:
print ( " Incorrect input ！" )
# Show
def Show_all(self):
for goods in self.go:
print ( str ( goods ) )
# add to
def Add(self):
goods_name = input ( " Please enter the product name ：" )
ret = self.check ( goods_name )
if ret != None:
print ( ' The item already exists ' )
print ( ' Whether to increase the quantity of goods ：（y/n）' )
while True:
pd = input ()
if pd == 'y':
goods_num = int ( input ( " Please enter the quantity of the product ：" ) )
old_goods = Goods ( goods_name, goods_num + ret.num, ret.cin, ret.cout )
self.go.remove ( ret )
self.go.append ( old_goods )
print ( " Increase success " )
break
elif pd == 'n':
print ( " Has returned " )
break
else:
print ( " Incorrect input , Re input ：" )
else:
goods_num = int ( input ( " Please enter the quantity of the product ：" ) )
goods_cin = float ( input ( " Please enter the purchase price ：" ) )
goods_cout = float ( input ( " Please enter the commodity shipping price ：" ) )
if goods_num > 0 and goods_cin > 0 and goods_cout > 0:
new_goods = Goods ( goods_name, goods_num, goods_cin, goods_cout )
self.go.append ( new_goods )
print ( " Add success " )
else:
print ( " Input error ！" )
# modify
def Modify(self):
goods_name = input ( " Please enter the product name to be modified ：" )
ret = self.check ( goods_name )
if ret != None:
print ( ret )
goods_name1 = input ( " Please enter the name of the modified product ：" )
goods_num = int ( input ( " Please enter the quantity of the modified product ：" ) )
goods_cin = float ( input ( " Please enter the purchase price of the goods after modification ：" ) )
goods_cout = float ( input ( " Please enter the revised commodity shipping price ：" ) )
old_goods = Goods ( goods_name1, goods_num, goods_cin, goods_cout )
self.go.remove ( ret )
self.go.append ( old_goods )
print ( " Modification successful " )
else:
print ( " This item is not available !" )
# Check , Before modifying and deleting a sale, call to check whether there is a product
def check(self, goods_name):
for goods in self.go:
if goods.name == goods_name:
return goods
else:
return None
def checkjs(self, goods_name):
for goods in self.js:
if goods.name == goods_name:
return goods
else:
return None
# Delete
def Delete(self):
goods_name = input ( " Please enter the product name to be deleted ：" )
ret = self.check ( goods_name )
if ret != None:
print ( ret )
print ( ' Delete item ：（y/n）' )
while True:
pd = input ()
if pd == 'y':
self.go.remove ( ret )
print ( " Delete successful " )
break
elif pd == 'n':
print ( " Has returned " )
break
else:
print ( " Incorrect input , Re input ：" )
else:
print ( " This item is not available ！" )
# sell
def Shop(self):
goods_name = input ( " Please enter the name of the product to be sold ：" )
ret = self.check ( goods_name )
if ret != None:
g_num = int ( input ( " Number of sales :" ) )
if ret.num - g_num < 0:
print ( " The quantity of this product is insufficient ！ Please add " )
else:
old_goods = Goods ( ret.name, ret.num - g_num, ret.cin, ret.cout )
self.go.remove ( ret )
self.go.append ( old_goods )
gret = self.checkjs ( goods_name )
if gret == None:
shop_goods = gGoods ( ret.name, g_num, ret.cin*g_num, ret.cout*g_num )
self.js.append ( shop_goods )
else:
shop_goods = gGoods ( gret.name, g_num + gret.gnum, gret.gcin + ret.cin*g_num,
gret.gcout + ret.cout*g_num )
self.js.remove ( gret )
self.js.append ( shop_goods )
print ( " After selling ：", end=' ' )
old_goods = Goods ( ret.name, ret.num - g_num, ret.cin*g_num, ret.cout*g_num )
print ( old_goods )
else:
print ( " This item is not available ！" )
# Summarize the goods sold on that day , Include the name of each item sold 、 Number 、 Total purchase price 、 Total sales price, etc .
def Summary(self):
for goods in self.js:
print ( goods )
print ( " The total purchase price of the goods sold ：", end="" )
x = 0
for goods in self.js:
x += float ( goods.gcin )
print ( " The total sales price of the goods sold ：", end="" )
y = 0
for goods in self.js:
y += float ( goods.gcout )
print ( y )
print ( " profits ：", y - x )
if __name__ == '__main__':
manager = GoodsManager ()
manager.Menu ()
